Motor-driven conveyor rollers basically consist of an electric drive motor in the interior of a conveyor roller tube, which sets the conveyor roller tube in rotation relative to an axle. In this case, the axle is typically held positionally fixed in a frame and fixed in terms of torque and may be formed by two individual axle stubs at both ends of the conveyor roller or else by a continuous axle body.
Motor-driven conveyor rollers are products which are subjected to various high requirements. A high degree of smooth running is required to keep the noise level low in conveyor devices which typically have multiple such motor-driven conveyor rollers. A low-cost production method is also required since products which are used in large quantities are involved. The availability of motor-driven conveyor rollers in different variants is also required. In this regard, for various applications, motor-driven conveyor rollers having different lengths of the conveyor roller tube are also required, in order to be matched to in each case specific product dimensions or conveying capacities. Furthermore, different requirements with regard to the rotational speed or conveying speed and with regard to the torque are imposed on motor-driven conveyor rollers.
A motor-driven conveyor roller in which a drive unit is arranged within a conveyor roller tube and is coupled to a gearing within the conveyor roller tube is already known from DE 20 2009 012 821 U1. The drive of the conveyor roller tube is realized by coupling of the gearing to an end-side cap which is coupled fixedly in terms of torque to the conveyor roller tube and in which an axle, which projects from the conveyor roller tube, is mounted.
A drive roller arrangement for a belt-type conveyor in which, likewise, a drive device and a gearing are arranged within a drum body is already known from DE 69306884 T2.
Drive devices in which a drive unit and a gearing are arranged within a cylindrical drum body and the drum body is set in rotation by said drive unit are likewise already known from DE 35 38 173 C1, US 2015/0068874 A1, U.S. Pat. Nos. 6,124,656 and 5,442,248.
It is fundamentally known to produce and to offer motor-driven conveyor rollers of differing type for this purpose. In this case, the components of the respective individual motor-driven conveyor roller are carefully coordinated with one another, and meet the imposed requirements overall, in that the electric motor and gearing are matched for example to the speed and torque required in the conveyor device, or in that an electric motor is, with regard to its power, matched to the conveyor roller tube length. Basically, the result thus achieved is a technically balanced motor-driven conveyor roller, which is coordinated with regard to its components in a manner matching one another and reliably achieves a desired long service life.
Motor-driven conveyor rollers are produced with different powers and power characteristics. Specifically for drum motors, but also for smaller motor-driven conveyor rollers, it is desirable to be able to provide embodiments with high rotational speeds and embodiments with large torques. This requirement has an effect on the entire drive train of the conveyor roller. In this regard, in addition to the drive motor, the gearing and the torque-transmitting components are subjected to high loads, these, however, being of different types, if on the one hand a motor-driven conveyor roller is configured with a particularly high rotational speed, or if on the other hand a motor-driven conveyor roller is configured with a particularly high torque.
In order to provide motor-driven conveyor rollers having such properties, different types of gearings are used. Use is often made of planetary gearings which, in particular, if a large torque is sought at the conveyor roller tube, are of multi-stage design and thus achieve a very large reduction ratio. As a result, very large torques act at the gearing output and in the torque-transmitting components of the conveyor roller from the gearing output to the conveyor roller tube, with simultaneously low rotational speed.
In other applications, use is made of gearings having only a low reduction ratio, partially also as gearings which are designed as a direct axle through drive and which have a direct drive from the drive motor to the conveyor roller tube. In the case of these types, very high rotational speeds of the conveyor roller tube and the rotation-transmitting components of the conveyor roller occur.
The gearing of a motor-driven conveyor roller and the torque-transmitting components are subjected to various—partly conflicting—requirements. Firstly, the gearing accounts for a large proportion of the running noises generated by a conveyor roller. With the objective of minimizing these running noises, use is made of gearings which consist largely of plastic, for example have a plastic housing and plastic toothed gears. However, this construction is not able to bear loads sufficiently, in particular, if very large torques are transmitted, and so gearings produced from metallic materials have proven to be successful for conveyor rollers that are designed for a large torque.
The integration of these different gearing types, with different output torques and output rotational speeds, into a conveyor roller necessitates matching to the loads occurring. A problem that arises is that this matching is complex in terms of production, and precisely when gearings from the extremes of the design spectrum, that is to say, having either a very high speed at the gearing output or a very large torque at the gearing output, are used, no satisfactory transmission of the torque from the gearing output to the conveyor roller tube is achieved.